import _ from "lodash"
import { JsonQLExpr } from "@mwater/jsonql"

/** Recursively inject table aliases
 * aliases is map of replacement to table aliases. For example, { "{a}": b } will replace "{a}" with "b"
 */
export function injectTableAliases(jsonql: any, aliases: { [from: string]: string }): any {
  // Handle empty
  if (!jsonql) {
    return jsonql
  }

  // Handle arrays
  if (_.isArray(jsonql)) {
    return _.map(jsonql, (item) => {
      return injectTableAliases(item as any, aliases)
    })
  }

  // Handle non-objects by leaving alone
  if (!_.isObject(jsonql)) {
    return jsonql
  }

  // Handle field
  if (jsonql.type === "field" && aliases[jsonql.tableAlias]) {
    return _.extend({}, jsonql, {
      tableAlias: aliases[jsonql.tableAlias]
    })
  }

  // Recurse object keys
  return _.mapValues(jsonql, (value) => {
    return injectTableAliases(value, aliases)
  })
}

/** Recursively inject table alias tableAlias for `{alias}` */
export function injectTableAlias(jsonql: any, tableAlias: string): any {
  return injectTableAliases(jsonql, { "{alias}": tableAlias })
}